الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The obesity epidemic is driving a large increase in type 2 diabetes mellitus (T2DM) and consequently setting the scene for an impending wave of cardiovascular morbidity and mortality. Obese children and adolescents demonstrate increased rates of early maturation, growth abnormalities, diabetes mellitus, obstructive sleep apnea, hypertension, steatosis, and polycystic ovarian syndrome, placing this group of children at risk for longterm health problems and reduced quality of life. A primary biochemical abnormality in most cases of T2DM is insulin resistance. The onset of insulin resistance commonly leads to relative insulin deficiency, with a slow decline in the regulation of blood glucose accompanied by hyperinsulinemia and elevated circulating free fatty acid (FFA) levels. Insulin resistance is a fundamental aspect of the etiology of T2DM and is also linked to a wide array of other pathophysiological sequelae including hypertension, hyperlipidemia and atherosclerosis. Reliable methods are essential to assess the presence and the extent of insulin resistance, the associated risk factors and the effect of pharmacological and lifestyle interventions. Simple methods to assess insulin resistance based on surrogate markers derived from an oral glucose tolerance test or from fasting insulin and glucose levels have been validated and widely used. The homeostasis model assessment of insulin resistance (HOMA-IR) is the most popular for epidemiological studies. C-peptide is the part of pro-insulin which is cleaved prior to cosecretion with insulin from pancreatic beta cells. Produced in equimolar amounts to endogenous insulin, it has been widely used as a measure of insulin secretion. Urinary c-peptide (UCP) is a non-invasive test, which can be performed in an outpatient setting. In patients with normal renal function, UCP quantity is reflective of 5–10% of total c-peptide secreted by the pancreas. In subjects with normal glucose tolerance urinary c-peptide to creatinine ratio (UCPCR) has been shown to correlate with 24 h urinary cpeptide, this suggests that UCPCR might be a simple, reliable, and convenient method of estimating C-peptide. Our study was done to compare different markers for assessment of insulin resistance in obese children and adolescents including urinary C peptide and Urinary C Peptide Creatinine Ratio (UCPCR) as novel markers for assessment of insulin resistance in obese children and adolescents. The present study included 60 children and adolescent who were classified into: I) group I: included 30 obese children and adolescents who had regular follow up in pediatric endocrinology outpatient’s clinic, Tanta University Hospital. They were collected during the period December 2018 to June 2020. II) group II: included 30 healthy children as a control group of matched age and sex to group 1 and who had normal BMI for age between 10th and 90th percentiles according to Egyptian growth charts. All the subjects were subjected to the following: - - Thorough history taking. - Full clinical examination: emphasizing on their: -Weight, Height, BMI, Waist circumference, Hip circumference. (All measures evaluated according to appropriate centiles.) -Skin finding of acanthosis nigricans. -Blood pressure. -Tanner staging. (Sexual Maturity Staging) -Laboratory investigations including: • Complete blood picture, Liver function tests, Renal function tests. • Blood cholesterol, Triglycerides, LDL, HDL. • Fasting insulin and Fasting blood glucose to calculate • (HOMA-IR): will be calculated using HOMA-2 Calculator. • HbA1c. • OGTT. • 2 hours post prandial Urinary C-peptide and urinary C-peptide Creatinine ratio (UCPCR). • Fasting serum C-peptide. Statistical analysis of the results was conducted, using the mean, standard error, student t-test, Chi square test and Linear Correlation Coefficient. Results: As regard clinical features of the studied groups: Comparison of clinical features in our study revealed that regarding weight, BMI, Waist/Hip ratio and systolic and diastolic blood pressure percentiles of patients were significantly higher than controls. As regard routine laboratory tests of the studied groups: ALT, AST, total cholesterol, LDL and triglycerides were significantly higher in obese patients than controls. As regard Insulin resistance: Fasting blood glucose, fasting serum insulin, fasting serum C peptide, HOMA-IR, OGTT and HbA1c were significantly higher in obese patients than controls. As regard urinary C peptide and UCPCR: Urinary C peptide and UCPCR were significantly higher in obese patients than controls. Urinary C peptide significantly correlated with acanthosis nigricans and diastolic blood pressure percentile. Also Urinary C peptide was significantly correlated with UCPCR, fasting serum C peptide, HOMA-IR, HbA1c, OGTT and BMI Z-score. UCPCR was significantly correlated with HOMA-IR.